Worm Compost Suppresses Plant Diseases

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We all know that composting is a great way to reduce waste, and vermicomposting can be a particularly effective method on the household level. When I wrote about worm composting becoming big business, there was also a lot of interest in the supposed disease suppressing qualities of vermicompost. Now an article over at the Cornell Daily Sun sheds a little more light on just how this magic black stuff can help keep our plants healthy.Looking at the work of Avon, New York-based Worm Power composting, the article by Jing Jin explores how worm compost helps suppress plant diseases. Worm Power is a commercial composting operation that feeds over 20 tons of dairy cow manure to eight million earthworms each week.

The compost is sold to gardeners and farmers, but the company is also working with Allison Jack—a plant pathology and plant-microbe biology researcher currently working on her doctoral thesis—to put its products through testing under lab conditions. The idea is to monitor the effects of vermicompost applications on plant growth, and to test the myriad of claims out there about compost's "magic qualities".

According to Jin, the research has shown that applications of Worm Power's compost can successfully suppress Pythium aphanidermatum - a water mold that is responsible for plant diseases such as damping off, where young seedlings rot away at the base of the stem:

"The microbes present in compost are the key to suppression. These microbes colonize the seed surface within eight hours of being planted in vermicompost. The microbes chemically modify the seed as it germinates so that signaling between the seed and the motile zoospores of P. aphanidermatum is interrupted, preventing the pathogen from accessing the plant. With vermicompost, "living microorganisms are required for the disease suppression to take place," Jack said."

It's impressive stuff, and just one more reason not to be throwing our food waste in the trash.